de6d010f4e
This PR extends the `struct` directive in tablegen to support nested
`custom` directives. Note that this assumes/verifies that that `custom`
directive has a single parameter.
This enables defining custom field parsing and printing functions if the
`struct` directive doesn't suffice. There is some existing potential
downstream usage for it:
a3c7de9242/stablehlo/dialect/StablehloOps.cpp (L3102)
Multi-Level Intermediate Representation
See https://mlir.llvm.org/ for more information.